1. Field of the Invention
The present invention relates to a working fluid which comprises plural halogenated hydrocarbons and is used in air conditioners, heat pumps and the like.
2. Description of the Related Art
Hitherto, as working fluids in air conditioners, heat pumps and the like, are used halogenated hydrocarbons derived from methane or ethane, which are also called fluorinated halocarbons. They work at such utilization temperature that their condensation temperature and/or evaporation temperature is from about 0 (zero) to about 50.degree. C. Among them, chlorodifluoromethane (CHClF.sub.2, R22) with a boiling point of -40.8.degree. C. is widely used as a working fluid in an air conditioner for a building and a large size refrigeration system.
Recently, depletion of the ozone layer in the stratosphere with fluorinated halocarbons is seriously discussed as one of the global environmental problems, and amounts to be used and produced of some fully halogenated chlorofluorocarbons (CFCs) which have high ozone depletion potential are limited by the Montreal Protocol. In future, their use and production will be banned.
R22 has an ozone depletion potential (hereinafter referred to as "ODP") of 0.05 when ODP of trichlorofluoromethane (CCl.sub.3 F, R11) is defined to be 1 (one). Though R22 is not a CFC, its production and use are expected to increase and it is expected that R22 will have significant influences on living in future, since the air conditioners and the heat pumps are and will be widely used. Therefore, it is highly desired to quickly develop a working fluid which has a small ODP and can be used as a substitute for R22.